With improved survival following breast cancer, there is increasing focus on the health-related quality of life (QoL) of breast cancer survivors. Although neighborhood disadvantage affects adult health behaviors, breast cancer incidence and survival, and QoL of the general population independent of individual-level factors, little attention has been directed toward such neighborhood factors related to QoL following breast cancer diagnosis. The following aims will be addressed in this revised application: 1) Determine the extent of geographic clustering of the change in QoL over time among women with and those without breast cancer at the level of the census tract; 2) Determine the extent to which the change in QoL over time can be explained by neighborhood disadvantage among women with breast cancer and among women without breast cancer; and 3) Identify potential pathways by which neighborhood disadvantage affects changes in QoL over time among women with breast cancer. The proposed prospective, population-based study will extend the current model of individual-level factors and QoL to a multilevel approach by including neighborhood indicators of social and economic disadvantage at the census tract level among women with breast cancer as compared to community-dwelling women without breast cancer. Women with breast cancer will be identified one year following their diagnosis by the Missouri Cancer Registry (MCR). Following consent, they will be interviewed at this time as well as one year later to assess changes over time in QoL. A population-based control group of community-dwelling women without breast cancer will be identified through random-digit dialing and interviewed at similar time points. A composite index of neighborhood disadvantage will be constructed from census data. The multilevel nature of the study makes it possible to identify barriers as part of hypothesized pathways that could be targeted by intervention studies aimed at several levels (e.g., individual and neighborhoods simultaneously) using a multi-pronged approach to improve QoL, as recently recommended by the Institute of Medicine.